1. Field of the Invention
The present invention relates to an x-ray monochromator for producing a monochromatic and highly non-divergent x-ray beam and a spectral measurement apparatus using the x-ray monochromator.
2. Discussion of Background
An x-ray monochromator is for producing a monochromatic x-ray beam by subjecting an incident x-ray to Bragg reflection. Perfect crystals such as single crystals of Si and Ge are used in such an x-ray monochromator. One x-ray monochromator is composed of a single monochromator-crystal which utilizes one reflection from the surface thereof, and another x-ray monochromator is composed of, for instance, a channel-cut type monochromator-crystal which is made from a single piece of crystal including a U-shaped inner groove, and utilizes two reflections from the inner flat walls of the groove.
In order to improve the energy resolution of such an x-ray monochromator, the provision of a monochromator comprising two monochromator-crystals to an x-ray diffractometer has been proposed as a filter for obtaining a particular incident x-ray beam.
Recently a number of devices provided with a substrate and a thin single crystal layer formed thereon have been utilized and the number is increasing. A thin-film measurement method using a XANEs measurement or total reflection is most suitable for the nondestructive structural analysis of such a thin single crystal layer and for in situ inspection of the thin single crystal layer.
However a conventional thin-film measurement method using the monochromator including a pair of monochromator-crystals, have the shortcoming that manual adjustment of the spatial relationship between the two monchromator-crystals is partially restricted, so that it is extremely difficult to adjust the configuration and posture of each monochromator-crystal and to obtain a sufficiently high precision of the relative positional configuration when the two monochromator-crystals are merely rotated in synchronism with the rotation of their rotary axes.
Furthermore, a conventional thin-film measurement method using a single monochromator-crystal by the XANES measurement method or total reflection method does not provide a sufficient resolution for use in practice. When the channel-cut type monochromator-crystal is employed in these measurement methods, a slit must be employed in order to obtain the high energy resolution which is necessary for use in practice. However the use of the slit not only decreases the intensity of the x-ray flux obtained, but also cannot improve the angular divergency of the x-ray beam.